JP4457622B2 - Inkjet printer - Google Patents

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to an image forming method for forming and fixing an image by an ink jet method using an ultraviolet curable ink that can be reacted and cured by irradiating ultraviolet rays.

  Conventionally, as an ink jet recording apparatus, an ultraviolet curable ink jet recording apparatus is known as an apparatus capable of forming an image even on a substrate having poor ink absorbability. (For example, refer to Patent Document 1). In general, an ultraviolet curable ink in which a photoinitiator sensitive to ultraviolet rays is contained in an ink is used, and the landing ink is irradiated with ultraviolet rays.

  In such an ink jet recording apparatus, until the ink is cured and fixed on the recording medium by ultraviolet irradiation, the dot diameter is changed due to expansion of the dot diameter, bleeding between the dots, penetration of the ink into the equipment, and the like. There is a problem that the image is disturbed, and it is preferable to equalize the time from landing on the recording medium to irradiation with ultraviolet rays.

  On the other hand, in Patent Document 2, a plurality of recording heads are arranged in series in the sub-scanning direction, and ultraviolet light sources are arranged at both ends of the recording head in the main scanning direction, so that the time from ink landing to ultraviolet irradiation. The dot diameter was stabilized by equalizing the values to obtain a high-definition image.

JP 2001-310454 A JP 2002-292907 A

  However, as disclosed in Patent Document 2, since the print heads are arranged in series, the print head main body becomes larger than the nozzle row, so that the carriage becomes larger in the sub-scanning direction, and the inkjet printing apparatus itself becomes larger. In addition, the cost increases due to the increase in size. Further, along with the increase in size of the ink jet recording apparatus, there has been a new problem that heat, ozone, and odor generated from the light source also increase as the size of the ultraviolet light source increases and the capacity of the light source increases.

  Therefore, an object of the present invention is to provide an ink jet recording apparatus using an ultraviolet curable ink that can reduce the size of the carriage in the sub-scanning direction and can reduce the size of the entire apparatus.

In order to solve the above-described problem, an ink jet recording apparatus according to the first aspect of the present invention provides:
A recording head formed on a surface facing the recording medium by forming a nozzle for discharging ink that is cured by ultraviolet rays onto the recording medium, and provided in association with the recording head, and from the nozzle of the corresponding recording head discharged and the ultraviolet light source is irradiated with ultraviolet rays to cure the ink after the ink landed on the recording medium, the recording head and the said ultraviolet light source to each plurality equipped, and a carriage which moves in the main scanning direction In an inkjet recording apparatus having
The plurality of recording heads each have a plurality of nozzles arranged along a sub-scanning direction orthogonal to the main scanning direction, and are arranged in a staggered manner along the sub-scanning direction ,
The plurality of ultraviolet light sources are:
Arranged in a staggered manner along the sub-scanning direction so that the distances in the main scanning direction to the corresponding recording heads are equal to each other,
The LEDs are respectively formed to have a length in the sub-scanning direction that is equal to or greater than a plurality of nozzles of the corresponding recording head .

According to the first aspect of the present invention, a plurality of recording heads are arranged in a staggered pattern in the sub-scanning direction orthogonal to the main scanning direction, and the plurality of ultraviolet light sources are distances in the main scanning direction to the corresponding recording heads. since There are arranged in the sub-scanning direction in a zigzag form so as to be equal, respectively, while stabilizing the dot diameter was equal to the time until the cured by ink ultraviolet light source which is discharged onto the recording medium from the recording head, The capacity of the ultraviolet light source is reduced, and the length of the carriage in the sub-scanning direction is shortened.

The ink jet recording apparatus of the invention according to claim 2
In claim 1,
The ultraviolet light source is arranged on both sides in the main scanning direction with the corresponding recording head interposed therebetween .

According to the second aspect of the present invention, since the ultraviolet light source is disposed on both sides in the main scanning direction with the corresponding recording head interposed therebetween , printing in both directions in the main scanning direction is enabled.

The ink jet recording apparatus of the invention according to claim 3 is:
In claim 1 or 2,
The nozzles of the recording heads are arranged so as not to overlap in the main scanning direction.

  According to the third aspect of the present invention, since the nozzles of the recording head are arranged so as not to overlap in the main scanning direction, color blurring occurs due to ink mixing before the ink is cured. Nor.

The ink jet recording apparatus of the invention according to claim 4 is:
In any one of Claim 1 to 3 ,
A cationic curable ink is used as the ink.

According to the fourth aspect of the present invention, since the cation curable ink is used as the ink, the ink on the recording medium is cured by irradiating the ultraviolet ray with a relatively low illuminance.

According to the invention described in claim 1, by arranging a plurality of the recording head in the sub-scanning direction in a staggered manner, and it is equal to each other a distance in the main scanning direction with respect to the recording heads corresponding to a plurality of ultraviolet light sources By arranging them in a staggered manner in the sub-scanning direction , the ultraviolet light source while stabilizing the dot diameter by equalizing the time until the ink ejected from the recording head onto the recording medium is cured by the ultraviolet light source. And the length of the carriage in the sub-scanning direction can be reduced. Therefore, while maintaining a high-definition recorded image, adverse effects such as generation of heat, ozone, and odor accompanying the increase in size of the ultraviolet light source can be reduced, and the ink jet recording apparatus can be downsized.

According to the second aspect of the present invention, the ultraviolet light source is disposed on both sides in the main scanning direction with the corresponding recording head interposed therebetween, and printing is possible in both directions in the main scanning direction. Therefore, it is possible to obtain a high-definition recorded image in a shorter time and to reduce the size of the inkjet recording apparatus.

  According to the third aspect of the invention, since the nozzles of the recording head are arranged so as not to overlap in the sub-scanning direction, color blurring occurs due to ink mixing before the ink is cured. There is no. Therefore, it is possible to obtain a higher-definition recorded image and to reduce the size of the ink jet recording apparatus.

According to the invention described in claim 4 , since the ink on the recording medium can be cured by irradiating the ultraviolet ray having a relatively low illuminance using the cation curable ink, the recording image with higher definition can be obtained. Can be obtained.

  Hereinafter, embodiments of the ink jet printer of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples, and it is needless to say that various modifications can be made without departing from the scope of the invention.

[First embodiment]
The ink jet recording apparatus 1 of the present invention is a serial ultraviolet curable ink jet recording apparatus. As shown in FIG. 1, a main body 2 of the ink jet recording apparatus 1 is provided with a rod-shaped guide rail 3. A carriage 4 is supported on the guide rail 3. The carriage 4 reciprocates along the guide rail 2 in the main scanning direction A by a driving mechanism (not shown).

  As shown in FIG. 2, the carriage 4 is mounted with recording heads 5Y, 5M, 5C, and 5K that eject ink of each color of yellow (Y), magenta (M), cyan (C), and black (K). In each of the recording heads 5Y, 5M, 5C, and 5K, a large number of nozzles 6 for ejecting ink toward the recording medium are arranged at a predetermined interval in the sub-scanning direction B.

  In the present embodiment, the recording head 5Y that discharges yellow ink and the recording head 5C that discharges cyan ink are arranged linearly along the sub-scanning direction B, and the recording head discharges magenta ink. The recording head 5K that ejects 5M and black ink is also arranged in a straight line along the sub-scanning direction B. The recording head 5Y and the recording head 5C and the recording head 5M and the recording head 5K are arranged with their positions shifted in the main scanning direction A, and the recording head 5Y, the recording head 5C, the recording head 5M, and the recording head. The heads 5K are arranged so that the nozzles 6 do not overlap with each other in the main scanning direction A, so that the recording heads 5Y, 5M, 5C, and 5K are arranged in a staggered manner. It has become. Note that the ends of the nozzles 6 of the recording heads 5Y, 5M, 5C, and 5K and the ends of the nozzles 6 of the other recording heads 5Y, 5M, 5C, and 5K are arranged as close as possible while being arranged so as not to overlap. It is desirable to make it.

  The carriage 4 has ultraviolet irradiation devices 7Y, 7M, 7C, and 7K for irradiating the ink landed on the recording medium with ultraviolet rays to be cured and fixed to the recording heads 5Y, 5M, 5C, and 5K. The recording heads 5Y, 5M, 5C, and 5K are arranged on both sides so that the distance in the main scanning direction A is equal. As a result, like the recording heads 5Y, 5M, 5C, and 5K, they are arranged in a staggered manner. Has been.

  Ultraviolet light sources 8Y, 8M, 8C, and 8K are provided inside the ultraviolet irradiation devices 7Y, 7M, 7C, and 7K. The ultraviolet light sources 8Y, 8M, 8C, and 8K are at least equal to or longer than the length of the nozzles of the recording heads 5Y, 5M, 5C, and 5K in the sub-scanning direction B, and are discharged onto the recording medium P. It is only necessary that the ultraviolet light that is sufficiently cured by the ink is irradiated with the same amount of light. As the ultraviolet light sources 8Y, 8M, 8C, and 8K, in this embodiment, a high-pressure mercury lamp, a metal halide lamp, a black light, a cold cathode tube, an LED (Light Emitting Diode), or the like is desirable.

  The central part of the movable range of the carriage 4 is a recording area for recording on the recording medium P. An ink supply unit 9 that supplies ink to an intermediate tank (not shown) mounted on the carriage via an ink supply path (not shown) is provided at the outer end of the recording area, which is a movable range of the carriage 4. It has been. A maintenance unit 10 for cleaning the recording heads 5Y, 5M, 5C, and 5K is provided at the other outer end of the recording area within the movable range of the carriage 4.

  The main body 2 of the ink jet recording apparatus 1 is provided with a transport mechanism (not shown) for feeding the recording medium in the sub-scanning direction B. The transport mechanism includes, for example, a transport motor (not shown), a transport roller, and the like, and transports the recording medium P in the sub-scanning direction B by rotating the transport roller by driving the transport motor. Further, the conveyance mechanism repeats conveyance and stop of the recording medium P in accordance with the operation of the carriage 4 during image recording, and intermittently conveys the recording medium P.

  A platen 11 that supports the recording medium P from the recording surface is provided in the recording area below the carriage 4. The platen 11 is composed of a flat member.

The ink used in the present embodiment is preferably an ultraviolet curable ink.
UV curable inks are broadly classified into radical polymerization inks containing radical polymerization compounds and cationic polymerization inks containing cationic polymerization compounds as polymerizable monomers and photopolymerization initiators. Among them, the radical polymerization ink has a problem that the radical polymerization reaction is easily inhibited by oxygen in the air.

  In this respect, the cationic polymerization ink is not easily inhibited by such oxygen. Such a difference between the cationic polymerization ink and the radical polymerization ink tends to be found not only in the ultraviolet curable ink but also in the photo curable ink in general. For this reason, in an apparatus in which the ink ejected from the recording head 2 and landing on the recording medium P is easily exposed to air, such as the ink jet printer 1 of the present invention, a cationic polymerization photo-curing type with little or no inhibition of the polymerization reaction by oxygen. Ink has better functionality and versatility. Therefore, in the present invention, it is particularly preferable to use a cationic polymerization type ultraviolet curable ink containing a cationic polymerization compound.

  In addition, as the recording medium P used in the present embodiment, various papers such as plain paper, recycled paper, and glossy paper, various fabrics, various non-woven fabrics, resin, metal, glass, etc., which are applied to a normal inkjet recording apparatus. What consists of material is applicable. Further, as the form of the recording medium P, a roll shape, a cut sheet shape, a plate shape, or the like is applicable.

  Further, as the recording medium P used in the present embodiment, known opaque recording media such as various papers whose surfaces are coated with a resin, a film containing a pigment, and a foamed film are also applicable.

  Next, the operation of this embodiment will be described.

  When the inkjet recording apparatus 1 records an image on the recording medium P, the transport motor operates to transport the recording medium P along the sub-scanning direction B. Accordingly, the carriage 4 is reciprocated along the main scanning direction A immediately above the recording medium P.

  While moving, the carriage 4 ejects ink of a predetermined color from the nozzles 6 of the recording heads 5Y, 5M, 5C, and 5K toward the recording medium P based on predetermined image information. The ejected ink sequentially reaches the recording medium P. The ink that has landed on the recording medium P is sequentially irradiated with ultraviolet rays by the ultraviolet irradiation devices 7Y, 7M, 7C, and 7K, and the ink is cured and fixed on the recording medium P. For example, in FIG. 3, when the carriage 4 moves from left to right along the scanning direction A, the ink droplets ejected by the recording head 5K are cured by ultraviolet rays emitted from the ultraviolet light source 8K of the ultraviolet irradiation device 7K on the left. Is done. On the other hand, when the carriage moves from right to left along the scanning direction, the ink droplets ejected by the recording head 5K are cured by the ultraviolet rays emitted from the ultraviolet light source 8K of the ultraviolet irradiation device 7K on the right in FIG. . That is, the recording heads 5Y, 5M, 5C, and 5K are discharged from the recording heads 5Y, 5M, 5C, and 5K by the ultraviolet light emitted from the ultraviolet light sources 7Y, 7M, 7C, and 7K behind the recording heads 5Y, 5M, 5C, and 5K in the carriage movement direction. The ink is quickly cured and fixed on the recording medium P. Thereafter, the conveyance mechanism is operated and the recording medium P is conveyed in the sub-scanning direction B, whereby an image is formed on the recording medium P. In addition, when ink adheres to the surface of the nozzle 6, the recording heads 5Y, 5M, 5C, and 5K are appropriately cleaned by the maintenance unit 10.

  As described above, according to the present embodiment, the plurality of recording heads 5Y, 5M, 5C, and 5K mounted on the carriage 4 are arranged in a staggered pattern in the sub-scanning direction B. The length can be shortened, and the inkjet recording apparatus 1 can be reduced in size.

  The ends of the nozzles 6 of the respective colors and the ends of the nozzles 6 of the other colors are arranged so as not to overlap with each other, but are arranged as close as possible to further increase the length of the carriage 4 in the sub-scanning direction B. The ink jet recording apparatus 1 can be further reduced in size.

  Further, since the ultraviolet irradiation devices 7Y, 7M, 7C, and 7K are arranged at equal distances at both ends in the main scanning direction A with respect to the recording heads 5Y, 5M, 5C, and 5K, the carriage 4 moves forward. In the backward movement, the time until the ink discharged from the recording heads 5Y, 5M, 5C, 5K is cured by the ultraviolet light sources 8Y, 8M, 8C, 8K is equalized, and the dot diameter is stabilized. In addition, since the ultraviolet irradiation devices 7Y, 7M, 7C, and 7K are also arranged in a staggered manner, the ultraviolet irradiation devices 7Y, 7M, 7C, and 7K are downsized, and the capacity of the ultraviolet light sources 8Y, 8M, 8C, and 8K is reduced. . Thereby, while obtaining a high-definition image, the generation of heat, ozone, and odor accompanying the increase in size of the ultraviolet light sources 8Y, 8M, 8C, and 8K can be reduced, and the inkjet recording apparatus 1 can be downsized. it can.

  In this embodiment, the case where two ultraviolet light sources 8Y, 8M, 8C, and 8K are provided on both sides of the recording head has been described. However, the ultraviolet light sources 8Y, 8M, 8C, and 8K are connected to the recording heads 5Y, 5M, 5C, and 8K. Even if it is provided on one side with respect to 5K, the same effect can be obtained, and the inkjet recording apparatus 1 can be miniaturized.

FIG. 1 is a schematic perspective view for explaining the ink jet recording apparatus of the present embodiment. FIG. 2 is a plan view of the carriage of the ink jet recording apparatus according to the present embodiment. FIG. 3 is a front view of the carriage of the ink jet recording apparatus according to the present embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 4 Carriage 5Y, 5M, 5C, 5K Recording head 7Y, 7M, 7C, 7K Ultraviolet irradiation device 8Y, 8M, 8C, 8K Ultraviolet light source P Recording medium

Claims (4)

A recording head formed by forming a nozzle that discharges ink cured by ultraviolet rays onto the recording medium on a surface facing the recording medium, and a recording head provided in association with the recording head. discharged and the ultraviolet light source is irradiated with ultraviolet rays to cure the ink after the ink landed on the recording medium, the recording head and the said ultraviolet light source to each plurality equipped, and a carriage which moves in the main scanning direction In an inkjet recording apparatus having
The plurality of recording heads each have a plurality of nozzles arranged along a sub-scanning direction orthogonal to the main scanning direction, and are arranged in a staggered manner along the sub-scanning direction ,
The plurality of ultraviolet light sources are:
Arranged in a staggered manner along the sub-scanning direction so that the distances in the main scanning direction to the corresponding recording heads are equal to each other,
2. An ink jet recording apparatus , wherein each of the LEDs is formed to have a length in the sub-scanning direction equal to or greater than a plurality of nozzles of the corresponding recording head . The inkjet recording apparatus according to claim 1, wherein the ultraviolet light source is disposed on both sides in the main scanning direction with the corresponding recording head interposed therebetween .   The inkjet recording apparatus according to claim 1, wherein the nozzles of the recording heads are arranged so as not to overlap in a main scanning direction. It said ink jet recording apparatus according to any one of claims 1 to 3, characterized in that using a cationic curing type ink.

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